True Dual Exaust
 

I wanna put the flowmaster 40 series on my 2 door s10 blazer. Could I put true duals on it or should I just do a single back?

True duals would be hard to fit under a blazer. The gas tank is in the way, at least on a four door. A properly sized single can flow just about as well as duals, and you can split it after the muffler, probably.

Just got me a decent welder and thinking about making me a true dual set up. Anyone have any ideas on how I could/should do it?

I wouldnt if the engines stock. Ive seen a few,and they usually lost a little torque. They sound great,but usually lacks a little power. Unless your in it for sound,go single 2 1/4 pipe,high flow cat,and a flowmaster (the 40 deltas sound great on 4.3s) with a 1ft dump behind it.

Ive had great results doing so on 4 different blazers.